The complicated jointing or sealing of cured EPDM is the major disadvantage for EPDM in numerous applications, such as, roofing and waterproofing applications, because EPDM is difficult to weld, and is therefore complicate and expensive to install.
There is a need for EPDM compositions that have good thermoplastic heat sealing characteristics. Such compositions should be processed and shaped on existing, state of the art processes and equipment; for example, using conventional compounding, extrusion, injection molding, calandering, and lamination equipment and processes.
International Publication No. WO 2010/009024 discloses cross-linked polymeric films, laminates, membranes or other polymeric articles, which show rubber like heat resistance (hot set) and dimensional stability above the polymer melting point, while maintaining heat sealing properties. For example, the invention provides a film comprising at least one layer formed from a composition comprising the following components: A) at least one polymer selected from the group consisting of the following: i) an ethylene-based polymer, ii) an ethylene/α-olefin/diene interpolymer, and ii) a C4-C10 olefin-based polymer; B) at least one polymer selected from the group consisting of a propylene/ethylene interpolymer and a propylene/alpha-olefin interpolymer; and wherein the film is crosslinked using radiation and/or chemicals.
International Publication No. WO 2011/079207 discloses compositions comprising an ethylene/alpha-olefin/polyene interpolymer, an ethylene/alpha-olefin copolymer, a filler, a cross-linking agent, and a blowing agent. These compositions can be used to form cross-linked foam and articles, such as automotive parts.
International Publication No. WO 2011/163176 discloses a crosslinked composition formed by thermally treating a composition comprising at least the following: A) an ethylene-based polymer that has a density less than, or equal to, 0.910 g/cc; B) an olefin-based polymer that has a melt viscosity less than, or equal to, 20,000 cP, at 350° F.; and C) a crosslinking agent.
There remains a need for crosslinked EPDM with the advantages of a thermoplastic polyethylene EPDM composition, which has good thermoplastic heat sealing characteristics. There is a further need for such compositions that can be processed and shaped on existing, state of the art processes and equipment. These needs and others have been met by the following invention.